bring bcdb mock to same `data` interface as gedis client

[muhamadazmy]

Currently we have a bcdb mock we use for development and testing, and a gedis client that actually works against bcdb/gedis.

Currently both the mock and gedis are growing a part, we need to have similar data inputs/outputs from both

[zaibon]

I started doing the change in bcdb_mock. Opened a draft PR: #336

it contains the update for nodes and farms. I did a quick test and it seems this code is compatible with the cockpit frontend. So that's a good start.